Aquatic Technology Pool & Spa, "Creating Water as Art."™

Aquatic Technology Pool & Spa, "Creating Water as Art."™
Pools as an art form - the way it should be!

Wednesday, June 24, 2009

Managing your water chemistry... maintaining an even keel.

Maintaining the water chemistry in your vanishing edge pool, infinity edge pool, negative edge pool, perimeter overflow pool, flooded deck pool, or perimeter overflow pool, is all about consistent & even monitoring, automated chemical control, and dispensing of chemicals.


There are a number of factors that contribute to the "balance of the water." The most important are the pH and the alkalinity. The alkalinity is the ability of the water to buffer the pH (or buffer chemicals that may effect the pH). The alkalinity is like an auto-pilot or cruise-control for the pH.

If the alkalinity is out of the acceptable range, then any small factor will cause a wild swing in the pH. This is called "pH bounce." Because of this, the alkalinity is the first thing that should be brought into line when balancing the water.

An ideal range for the alkalinity is 100-120 ppm (though 80 - 140 ppm is acceptable).

pH 7.4-7.6

The pH of the water, determines if it is acidic or basic. Either extreme can have disastrous effects on the pool finish, equipment, or plumbing. When the pH is out of range, bathers may complain of eye discomfort or other ailments.

An acidic pH will cause the water to become aggressive. It will etch the plaster and cement finishes around the pool. Worse yet, it will dissolve the metallic components of the pool. The most expensive metallic component is the copper heat exchanger within the pool heater.

The ideal range for the pH is 7.4 - 7.6 (though 7.2 - 7.8 is acceptable).


After the alkalinity & pH are brought into range, the next adjustment is the sanitizer. Chlorine is the most common and least expensive of the available sanitizers. The acceptable range is 1.5 - 3 ppm, though 4 - 5 ppm is absolutely fine. A commercial spa should be maintained at much higher levels - 5 - 6 ppm.

A residential pool should be maintained at 3.0 ppm. The higher levels ( 4 - 5 ppm) should be established, prior to a large party or heat spell. Try not to allow the levels to drop below 3 ppm, as this will prevent the need to shock or take other corrective action after the party.

Total Dissolved Solids

Like it says, total dissolved solids (TDS), is the sum of all of the "junk" in the water. It includes dissolved minerals, salts, etc. We refer to this as the "junk in the trunk." When the TDS exceeds approximately 1500 - 1800 ppm above the initial starting point, then it is time to "dump some water." If the make-up water is "soft water," the dilution process will occur much faster (though the salt in the water will add some to the TDS).

Calcium Levels

Calcium is required to prevent the water from becoming aggressive. If there is not a sufficient amount in the water, it will seek an equilibrium and literally draw calcium from the plaster, tile grout, or other cementitious material.

A minimum of 200 ppm is required to prevent aggressive water. However, should the calcium level rise to 400 ppm or above, you can get scaling. Any drastic change in pH (like when adding liquid chlorine), and you can precipitate the calcium out of solution. It will attach to the plaster & cause a rough bumpy surface.

If the water begins to draw the calcium out of the plaster, the plaster surface will begin to feel like sandpaper.

Tile Scaling & Haze Build-up

A build-up of a white film or haze on the tile has nothing to do with the service company not scrubbing the tile... it is merely from the evaporation of water in the pool. As the water evaporates, calcium is left on the tile. Over time, it begins to cause what appears to be a haze.

It is actually calcium, like what is left on your drinking glasses in the dishwasher. To remove it is an additional cost, just like having your car detailed & waxed. Most pool service companies can remove the hazy build-up with specialty chemicals (high strength acids). These acids work by dissolve calcium, but they are "stupid" chemicals because they do not know the difference between the bad calcium (on the surface of the tile) and the good calcium (in the grout between the tiles). The use of these acids more than likely will damage the tile's grout.

An alternative is to hire a firm that utilizes "bead blasting." It is like sandblasting, but fine glass beads are used instead of aggressive sand. Various sizes of glass beads are available, down to very fine like talcum powder.

To prevent (or greatly reduce) the build-up of scale on the tile, a water softener on the fill line can remove all of the calcium from the water. You will have to monitor the calcium levels to maintain the 200 ppm minimum that is required.

But, it is much easier to add calcium, than to remove it. Though a water softener can cost $1000, living with the unsightly build up & the cost of removing it will quickly cost more than that (ROI).

Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa

Tuesday, June 16, 2009

Perimeter Overflow Pool, Flooded Deck Pool, Slot Overflow Pool... or who forgot to turn off the fill line?

Whether you call them waveless pools, overflow pools, perimeter overflow pools, slot overflow pools, knife edge pools, flooded deck pools, slot edge or wet edge pools, zero edge, wetted edge, no edge, or flooded coping pools, or wet deck pools, they all provide essentially the same appearance... that someone forgot to turn off the fill line. They are not to be confused with vanishing edge, negative edge, infinity edge, or disappearing edge pools, though the basic hydraulic principals are the same.

While these pools appear simple, they are actually quite complex. It is what you can't see that makes them complex. To make their design even more difficult, their hydraulic systems are a hybrid of pressurized returns and gravity drain lines.

Adding further to their complexity, they must have remote holding tanks, called surge tanks. The size of these tanks must be carefully calculated to provide enough water to raise the pool (to flood level) and continue the flooding process until that water returns to the surge tank. This quantity of water must be held in storage, plus a quantity necessary to prevent the tank from being pumped dry (a common mistake).

The capacity of the gravity drain lines must be carefully calculated, so that the amount of water held in reserve can be calculated. The time it takes for the water to begin to return to the holding tank is another critical calculation. The pitch (slope) of the gravity drain lines also determines the velocity that the water travels. Too slow, and the water cannot scour the debris in the lines. Too steep, and the entry point of these lines within the tank, drops significantly below grade. The further away from the pool the tank is located, the larger (or deeper underground) the tank must be placed - as the descending slope of the drain line gets lower & lower the further from the pool it travels. These gravity drain lines also cannot be calculated at their maximum capacity, as they must maintain some "freeboard." That is air in the top of the pipe. This prevents the formation of suction & a really annoying sucking sound!

The tank must have additional storage capacity to allow for displacement from the pool. Displacement comes primarily from wind and from bathers. Now there's a novel idea - people actually swimming in the pool! I cannot tell you how many of these tanks I have seen that were undersized. Every time someone went swimming, a few hundred to a thousand gallons of water was forced out of the tank's overflow line, only to have to be replaced when the fill line turned on.

On the opposite side, the lack of understanding of the hydraulic complexities of these pools, oftentimes results in the surge tank being WAY over sized. While there is nothing wrong with an over sized tank, it is a waste of money, labor, materials, and energy to build them over sized. Having to filter & chemically treat a few thousand gallons of extra water adds up over time.

The lack of proper planning, oftentimes leads to the neglect of maintenance of these tanks. This is where all of the large debris from the pool settles. If the builder designed the tank improperly, this debris is never drawn into the suction line, and therefore the pump strainer basket or filter.
These tanks should be outfitted with main drains, inlets to direct the flow towards these drains, auto-fill lines to also assist in the debris management, ladder rungs for personnel access, vacuum ports for cleaning, personnel access hatch over the ladder rungs, lighting (when fiber optic or low voltage is used on the project), and most importantly, a strainer. The strainer sifts out the large debris before it is deposited onto the floor. I have my own design for a SS basket placed in the path of the incoming line. A smaller lid is placed over this strainer basket to facilitate inspection and servicing of the basket.

By failing to make servicing these tanks easy, the service personnel will simply fail or neglect to service these tanks. At least 2X each year, they need to be drained, rinsed out, and vacuumed with a shop vacuum. An alternate approach, is to drain them to within 12" of the floor, and if one was installed, utilize the internal vacuum port in the floor with a pool vacuum to collect the debris into the pool filter system. This is best performed immediately before the filters are serviced 2X annually (cartridge or DE).

This brings us to filter selection... DE filters are not the wisest choice. They are simply too difficult to recharge after they are back washed or serviced, without the installation of a slurry line or tank.

The detail that is used on the edge of the pool where it meets the water, is one of personal preference. The current rage and most difficult to execute, is the knife edge. I will discuss this technique in detail in another blog.

Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa

Friday, June 12, 2009

Fountain Forced Perspective Optical Illusion Catherine de Medici Fountain

Vanishing edge pools, negative edge pools, infinity edge pools, perimeter overflow pools, hillside pools, slot overflow pools, knife edge pools, flooded deck pools, wet deck pools, spa, and fountain expert witness Paolo (Paul) Benedetti, discusses one of his favorite fountains - La Fontaine de Médicis (Fountain of Medicis) in the Jardines de Luxembourg, Paris, France (in Paris' Luxembourg Quarters) and design innovation.

Marie di Medici was married to Henry IV, the King of France. Homesick for her native Florence, she nagged her husband until he built her a palatial mansion & grounds. The results were a palace and gardens that would remind her of the childhood palace, where she grew up as a young monarch in Florence. I hope that it cured her homesickness!

On a recent trip to Paris, I stumbled upon a fountain in the Jardines de Luxembourg. The gardens surround the Palais de Luxembourg, which have been converted into a public park. The palace building now houses the French Senate.

The baroque fountain was built in 1625, and was designed by engineer Florentin Thomas Francine. It is comprised of three niches with a pediment ordained with the coats of arms of France and the Médici family. In the 1860's the fountain was relocated & retrofitted. Alphonse de Gisors restored the coat of arms and created a 50 meter water lane, lining the lane with trees. The centerpiece sculpture from the original fountain was placed at the end of the lane.

However, the most unique feature of this fountain is never discussed in any of the descriptions or narratives about it's design... the appearance that it is out of level! Even in the mid-1800's designers were pushing the extremes of design!

It is apparent by looking at the fountain, that the water alley in front of it, pitches towards the back, being out of level almost 3 of feet over it's length! We all know that water always seeks it's own level, so the fountain must be out of whack! (Click on the image to enlarge it & get a better view of the illusion)

I spent the better part of an hour in the rain, measuring the urns, pedestals, railings while trying to determine exactly what they did to executed this optical illusion. I knew that they had altered the scene, but I wanted to understand EXACTLY how they pulled it off. It wasn't until a few months later that it dawned on me... they altered the horizon to trick the viewers' peripheral vision, thereby fooling the mind's eye.

The adjustment of our perceived reality in this manner, is called "forced perspective." This fountain, is by far the best public example that I have ever witnessed.

There are a dozen world class aquatic designers plying my trade in the world today. But, I can guarantee you that there only 2 or 3 of them (I am one of them) who have an understanding of the subtle techniques to "fool the minds eye." To me, being able to force the mind into believing something that is not reality, is the ultimate sense of design - the ultimate understanding of your art, physics, the environment & human body. A designer who is able to execute these techniques with swimming pools, spas, fountains & water shapes is at the pinnacle of the watershape design industry.

I have developed a number of design elements, that I occasionally incorporate into projects, when the client or project warrants such illusions.

I have played with the refraction of light through water, creating illusions that curved surfaces flatten out, or that flat surfaces curve. This is an excellent illusion to use when creating bowls of water. The outside edges can appear to be flat, which our mind tells us should not be able to hold water, yet it does. It is because the viewer's eye sees the refracted image of the underwater structure as being flat.

It took many mock-ups and a series of trial and error experiments, to find the right combination of angles, finishes, proportions and depths to create this illusion. Yet it is satisfying to see a person's reaction the first time they witness the execution of this detail.

Another illusion that I employ is the blending of color. A true watershape designer understands that water filters out certain spectrums of light. Using the science of physics and color theory (the blending of primary & secondary colors), that are always constant, a designer can alter the perceived colors. Colors in the shallow end of the vessel appear to be one color, while in the deeper water (where the greater amount of water filters out more of the affected spectrums of light) the colors appear different. This is because the human eye blends the remaining colors of the light spectrum (that are not filtered out) that are reflected back at the viewer along with the color of the bottom of the vessel. The brain perceives these blended colors as the "true" color of the bottom, when in fact that is not true. This is why there appears to be a gradient shading of the colors as the water gets deeper.

Using artificially colored lighting in & around the pool can also alter the perceived colors. Again the ability to predict the outcome, through the use of color theory, is what puts the leading artists in the watershape industry at the top of their game.

Understanding and using these principals allows a designer to deliver a body of water that exhibits deep hues of a desired shade of color. My clients who want a green pool, never receive a pool with a green finish. I use physics, color theory & the blending of colors to create the shades and hues that I desire, based upon the depth of the pool. I can even create an intensified gradient that is natural and predictable.

Another illusion that I use is water's ability to transmit light. I have been able to light thin sheets of water spilling over a weir, and give the illusion that the water is lit by a horizontal ribbon of light - though there is no light source visible.

I have been able to create absolutely perfect columns of water rising 6-8 feet out of the floor of a fountain... a virtual vertical laminar. I have been able to eliminate the water falling back on itself, disrupting the laminar effect. Impossible you say? You can't turn off gravity! You're correct, but we're talking about illusions here... it has the illusion of being a vertical laminar (virtual laminar). At night the effect it astounding, as I have lit these columns of water from underneath - they appear to be 4-6" diameter vertical columns of water 6-8 feet high. Viewed from a distance of 20 feet, it is absolutely amazing.

I have suspended spilling vessels in mid-air, giving them the illusion that they are levitating with no attached pipes or wires, but they are still able to spill water. Our brain says "I see it, but don't believe it." The response is always, "how did they do that?" Being able to identify things that one observes in their daily life & travels, modifying & innovating them for use as a watershape is an innate ability, again not an ability that many individuals in the watershape industry possess.

The ability to observe the world around you, dissect the illusions and forced perceptions that you experience, and incorporate them in new and innovate ways is the mark of a watershape designer who is at the top of the mountain. One who can constantly deliver something new, surprising, and creative - and not a simple rehash of something that has already been done.

This is the designer - an artist, inventor, & innovator - that you deserve on your next project.

Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa

Tuesday, June 9, 2009

Failure of Glass Mosaic Tile - Cracks, Fractures, Fissures & Spalling

Paolo Benedetti - Designer & internationally renown expert consultant for hillside pools, vanishing edge pools, infinity edge pools, negative edge pools, disappearing edge pools, slot overflow pools, perimeter overflow pools, knife edge pools, wet edge pools and spas, and founder of Aquatic Technology Pool & Spa, discusses recent glass tile mosaic failures, namely fracturing & fissures, and all contained some recycled glass!

Though glass mosaic tiles have been around for centuries, their use in swimming pools & construction projects has exploded exponentially in the last decade. Many new players have joined the ranks of glass tile manufacturers. However, as the use of the material has grown, so have the problems.

Do not get me wrong, glass mosaic tile swimming pools, spas, and fountains are the top of the line! They are the pinnacle of pool finishes, and installed correctly should last for decades. I have glass mosaic tiles in my own backyard! And they are performing wonderfully, I might add!

The primary issue is the lack of a minimum industry performance standard for glass tile. The most important factor missing is a standard for their performance against thermal shock. Adding to the problem, is the current trend to be "green." This has led a number of manufacturers, both domestic & foreign, to utilize recycled glass for a portion of their production. Many Asian factories have no concern for the quality of the raw materials - glass is glass! The images shown here are from various projects from around the country - and all involve manufacturers who use some recycled glass in their tiles.

The use of recycled glass in the making of mosaic tiles, especially those that may be subject to any temperature differentials, will result in internal fractures/fissures within the tiles. While this will not lead to the glass tiles crumbling or decaying, it will cause unsightly fissures within the tiles - like those found within an ice cube. If these "cracked" tiles are subject to any subsequent impact or external stresses, they may crack or come loose - resulting in sharp pieces of glass tile on the floor. In a swimming pool, spa, steam bath, or shower application, this will definitely result in lacerations.

Over the past 5-10 years, a number of manufacturers that utilize recycled components have been experiencing performance issues with their materials. In most instances, they have been able to keep these cases isolated. In every instance that I am aware of, the property owner & installer have been led to believe that they are alone in their troubles. (click on the image for an enlarged image and a closer look) The "factory experts" have always blamed the installer for a faulty installation, leaving the installer to defend themselves against the homeowner. They will cite the use of "unapproved setting materials," failure to exactly follow their installation instructions, or the failure to follow proper curing procedures as the leading causes.

However, when the T's are crossed & the I's dotted, and a project is installed to the EXACT letter of the directions & standards, and there is still a material failure - where do the manufacturer's lay their blame? Again, they blame the installer & the installation.

They will grasp at straws, throwing out every excuse they have ever used - even going so far as to blame the concrete structure. This may have worked on a pool that was sliding down a hillside, but for a project that was supervised by the manufacturer of the setting materials, a site visit from the tile manufacturer, inspections by the structural engineer, inspections & observations by the geotechnical engineering firm, independent laboratory testing of the materials, deputy inspectors inspecting the reinforcing steel & monitoring the shotcrete placement, psi testing of the in-place shotcrete, complete documentation & tracking of all materials & batch numbers, and documented compliance with all TCNA & ANSI standards - they simply look like the fools that they are. And they begin to paint this segment of their industry with a big brush of cow dung.

However, with the advent of the internet, the "victims" of these manufacturers are bound to come together to compare notes. It is starting to happen. Here are some of the findings...

In every instance the cracks are totally random - they go opposite directions and are not in adjacent tiles. As can be seen in the image to the right, the cracking is totally random. (click on the image for an enlarged image and a closer look) The grout is intact and the cracking does not extend through to the setting material, so apparently the thinset is not the cause. These were the tile where we were able to duplicate similar cracks in loose unset tiles, so the setting materials & grout cannot be the cause.

When the manufacturers blame the installation, they will almost always try to hang their hat on something, even the smallest detail. Maybe in the end they will "be a nice guy and provide replacement tile." Whoopdie doo! It is the installation where the money is!

They may blame "unapproved" thinsets & grouts. Almost every commercially available thinset that is approved for submerged applications, meets the appropriate ANSI standards. Some manufacturers claim that some thinsets grab to tightly, preventing the glass from expanding & contracting. However, they are playing on the installer's naivety regarding material science. A 1" square mosaic tile expands to infinitesimally, it is almost unmeasurable. To blame a thinset for this internal cracking is ludicrous. For this to actually occur as they claim, there has to already be an inherent stress present in the tile.

These same manufacturers also blame epoxy grouts, as being too rigid and inflexible, thereby preventing the glass mosaic tiles from expanding. Again this argument is laughable... Here's an experiment your child can do: take a pair of pliers & attempt to crush a equivalent size of tile & epoxy grout. The child will not be able to crush the glass tile, while the grout will explode as it is pulverized. It will be apparent to even a 5 year old, that the glass is much stronger than the epoxy grout. Additionally the expansion of the tile, being sooo microscopically small could not develop such pressures - but if there was a pre-existing stress within the tile...

Some have blamed the use of additional admixes (latex fortifiers), when the thinset manufacturer does not advise to. While this will effect the performance of the thinset & grouts, it will not cause them to become so hard or inflexible, as to crack the tile. Again, they are pretending to be "experts" in the field of material science, and because they are from "the factory" - the property owner believes them. Most "factory experts" are merely businessmen or trades persons who, like myself learned through the "school of hard knocks." I've yet to meet one that possessed a formal degree in material or molecular science [I have a chemical engineer/MBA/JD, a polymer research chemist (this is material sciences up the wazoo), and 2 orthopedic surgeons (biological science) in my immediate family].

To reinforce this point - these same manufacturer's tiles can be made to crack by merely exposing them to the thermal changes in a typical backyard spa. Left loose in a plastic tray (and therefore not subject to any external forces from thinset or grouts) and subject to the normal temperature changes from 60-104º F - these tiles will begin to display the same internal stress cracks that are found in an installed application. So guys, how can it be the thinset, when the tiles crack while loose?

Another case I looked at involved tumbled glass tiles that were installed in a steam shower. The edges of the tiles were spalling. And this was only occurring on the side of the shower opposite the shower & steam heads. As you can see from the image to the right, the edges of the tiles are "chipped." (click on the image for an enlarged image and a closer look) First, the chipping was blamed on rough handling during installation - but I dismissed that notion. Look at the edges of the tiles... if they were "mishandled" the chips would have been filled in (even slightly) during grouting. These are recent, fresh & shiny chips that show no sign of grout in them - proof that they occurred after installation. And it could not be from any impacts - they are from the floor to 6' high! To further reinforce this failure, we were able to recover shards of glass from the floor of the shower using duct tape... guess what we found? ...small chips of glass, exactly the size of what was coming off of the installed tile on the wall. Coincidence? Hardly!! One of the unique characteristics of glass is that it radiates heat quickly. So, glass tile installed on a wall in a room heated to 80˚F, may be 65-70˚F. When an "instant hot" 120-130˚F shower (such as those with recirculating hot water) or a 160˚F steam shower blasts the surface of the tiles with a severe temperature shock - something has to give! And that something is the glass tile - lots of little sharp pieces of it. Then Mr. or Mrs. Zillionaire steps barefooted into a glass shard torture chamber - YOU are going to be the 2nd person that they are going to call (you know that their attorney is going to be the number one!). The cool underlying surface of the glass is still at 65-70˚, while the surface is 130-160˚F! The glass simply cannot change temperature quickly enough throughout it's thickness, so something has to give. Yet, these tiles are marketed for use in showers! But there are no thermal shock standards for this material... these are cases where the government needs to establish standards to protect the consumers. Like the exploding Ford Pinto - bad designs & products need to be made safe! Broken glass is inherently dangerous around showers, bathrooms, swimming pools & spas, and pool decks.

In fact, these same tile can be made to crack & fissure, by merely laying the sheets of tiles out in the sun... now, how can an installer cause that????

Still, these manufacturers blame the installation procedures. Okay, for just a minute, let's assume that it is the installation. Then, why do I possess multiple factory assembled sample boards, that exhibit the same internal stress cracking that the installed product is exhibiting in the field? These are 1 foot square sheets of tile thinset to a 3/4" thick piece of plywood & grouted with a polymer fortified thinset - all assembled by the manufacturer in their factory controlled conditions. And guess what? They still cracked!

I know of a project in Southern California where the tiles had been installed, and were in the "thinset curing stage," when random tiles started to crack. And guess what? The factory blamed a faulty structure.... (click on the image for an enlarged image and a closer look) But the commercial hotel developer, general contractor, swimming pool contractor, structural engineer, soils engineer, and materials testing laboratory hit back right between the eyes. And the factory took back the balance of almost 30,000 square feet of unmounted tile. Hmmm, do you think that the factory destroyed the returned tile...??? This is probably the very tile that you're going to receive in your next shipment! And then you're going to be blamed for your faulty installation!

Where am I going with this...

There needs to be a standard established for the manufacturing of glass mosaic tiles. Currently there is an ANSI Standards committee formulating these standards. But guess who is sitting on these committees? You guessed it - representatives from these very same manufacturers! Do you think that there is going to be any substantial thermal shock standard established that is going to protect the public from cracking glass tiles? Very doubtful. The fox is in charge of the hen house.

If they are not willing to subject themselves to this higher standard, then they need to disclose to the public, what extremes a particular product can safely handle. Maybe they need to establish a tiered rating system with temperature extremes based upon maximum rates of rise X a time variable. A consumer friendly A-B-C system would be ideal, with A tiles being the most shock resistant (on par with Pyrex) and C being the poorest quality. Every tile sold in the US (even imported tiles) would have to meet these standards. To maintain their thermal shock rating, a manufacturer would be required to submit samples for regular & periodic quality control checks by an independent testing laboratory (UL), to verify that the standards are still being met.

This brings us to the science behind the problems of utilizing recycled glass as a component of the raw materials. Mixing raw & recycled materials, results in a blend of materials (down to the microscopic level) with differential expansion indexes. Glass tile is very dense. The slightest thermal changes results will result in minuscule amounts of expansion. However, if this expansion is occurring at different rates within the matrix of the material (as what occurs with blended recycled materials), a stress crack may result.

Additionally, the manufacturing processes employed by a manufacturer may lend itself to "stressing" the tiles. Most manufacturers utilize a "press" much like a cookie cutter to cut the tiles out of sheets of molten glass. This process seems to render the fewest problems. These tiles are recognizable by their smooth edges, uniform size & thickness. The edges will often be tapered, being wider at the top of the tile. They may also exhibit slight marks on the edges from the press (these are not visible once the tile is set & grouted).

The second procedure is the actual cutting of the individual tiles from a hardened irregular shaped sheet of glass. The cutting procedure actually causes micro-fractures & stresses within the edges of the glass. Removing these stresses requires that the tiles receive an additional firing. These tiles are recognizable by an edge that is perfectly straight & vertical, without any marks from a press. If the tiles were re-fired, the edges will not be sharp like freshly cut glass, but very slightly rounded.

The third process is a hybrid of the press & cutting process, where the press stamps out the shape, but does not sheer the glass into individual tiles. The sheet is later "cracked" along the depressions in the sheet left by the press - resulting in a distinctive irregular edge. This "cracking" process also imparts micro-stresses into the tile. These tiles are readily recognizable by their irregular shape and oftentimes sharp edges. If the tiles were subject to re-firing to relieve the internal stresses, these sharp edges will have softened.

The final major process is the actual pouring of molten glass into molds. These tiles vary in thickness, even within an individual tile. A series of nozzles squirt molten glass in what looks like ice cube trays. The bottom of the mold forms the top of the tile. Some manufacturers follow this with a press, to stamp in a texture or stand offs into the back of the tiles. However, if the mold was not sufficiently filled, or the glass too cool, the glass will have not flowed level within the mold. They tend to be thicker than all of the prior methods, and therefore even more susceptible to exhibiting internal fissures.

An added issue is the cost of energy. It costs a lot of money to run a glass kiln & foundry. Many manufacturers do not follow proper annealing procedures - that is the slow controlled cooling of glass. The glass is transported through a temperature controlled linear kiln (called a Lehr), where the temperature zones within the kiln slowly decrease. Failure to properly anneal glass will result in the glass cracking or shattering when subject to the slightest temperature or mechanical shock - HEY DOES THAT SOUND FAMILIAR? There is no way by looking at glass tile with the naked eye, to see these inherent stresses. There is also no way to verify that the manufacturer is not "speeding up the annealing process" to save themselves some money. Remember, it's all about the Benjamin's!

So far the manufacturers that utilize virgin raw materials, and forgo the use of recycled glass in their products, have been spared the agony of their products cracking. My personal brands of preference include:,,,

While I am not fond of their color renditions and the silica speckles in their tiles, another brand that I have had success with is "Colorines Mosaicios" manufactured in Mexico. They are available exclusively through DalTile, as they were purchased by DalTile a few years ago.

To summarize the characteristics of glass mosaic tiles that tend to exhibit internal stress cracks:

Manufactured using recycled materials - they key commonality.
Manufactured in Asia (most Asian manufactured tiles are crap)
Improper annealing (how can you possibly know?)
Method of manufacture
Size & thickness (thinner & smaller mosaics seem to perform better)

Just because a glass mosaic tile is from a well know company, bears a prominent designer's name, is from a large company, or the product is in every tile showroom you walk into, does not mean that it is a quality glass mosaic. A lot of these glass tiles will perform wonderfully as a kitchen backsplash, but will fail miserably when subject to any climate changes or thermal shock.

Rules to live by:
1. By all means, follow the manufacturers installation instructions to the letter! Do not bootleg anything! Only follow the TCNA standards & recommendations.
2. Only use setting materials recommended by the manufacturer - if they do not specify brands & specific products, make the inquiry in writing! Keep all of your receipts. When you take delivery of the setting materials, note the lot numbers on the receipt.
3. Take lots of pictures. Digital pictures are free! be sure to track the dates specific areas were floated, set, and grouted. Be sure to follow the proper cure times before moving on to the next phase. Documentation is the key! It does not hurt to keep a color coding system, outlining areas with colored tape, so that they are readily identifiable in the photographs.
4. If it is an extremely large project (high risk & high gain), be sure to involve the manufacturers during the planning & installation process. Invite site visits & document the dates & progress on those visits. Follow up with a thank you letter & document any recommendations & comments.
5. Additionally, do not be afraid to send samples of the products to an independent testing lab for analysis and thermal shock testing. A few thousand dollars spent in advanced will save hundreds of thousands of dollars later.
6. Be an informed consumer.
7. Read the manufacturer's warranty before making your purchase.
8. Consider having the manufacturer post a bond or purchase an insurance policy to guarantee the product performance - if the project size warrants it.
9. Read the manufacturers warranty - some are so lame that they provide a warranty until you open the box or install the product! Read this joke from :


Limited Warranty Terms and Conditions

All products ("Products") sold by Hakatai, Enterprises, Inc., hereafter referred to as the "Company," are subject to this Limited Warranty.

Limited Warranty

The Company warrants that its Products, if properly stored and transported, will be free from defects in materials and workmanship from the date of sale until the date the product is installed ("Warranty Period"). THE PURCHASER SHALL EXAMINE ALL PRODUCTS FULLY PRIOR TO INSTALLATION. If a Company Product is found to be defective during the purchaser’s examination, and the purchaser submits the written service request required herein, the Company will, at its option, replace the Product with a Product that is at least functionally equivalent or refund the purchase price..."

"...Warranty Limitations and Exclusions


WOW, they offer a complete warranty until I install it! And I have to declare any defects prior to installing it.... hmmm, that has "confidence in our product" written all over it doesn't it?! It should say "Warranty Scam"!

I doubt my clients will just let me stack the boxes in their backyard & collect my money. If they are not willing to stand behind their product - then this should set off alarms in your head... Warning! Warning Will Robinson! Warning! Aliens approaching! Run for safety (with your $ in your pocket!). They provide a taillight warranty, when the headlights are still in your eyes! TURN and RUN!

Remember, the manufacturer may have a strong warranty backing their product, but no one can force them to pay out, except you and your lawyer!

They will do everything they can to point the blame at YOU!

NOTE: In the accompanying images, some of the tiles appear to have white cracks across the surface. These are actually casting marks or imperfections that collected grout in them & became highlighted. Look inside the tiles for radial cracks. Click on any image to view a super-sized version.

Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa

Monday, June 8, 2009

A Technicolor Dreamcoat

Paolo Benedetti, founder of Aquatic Technology Pool & Spa - Vanishing Infinity Negative Disappearing Perimeter Knife Edge Swimming Pools Spa Expert

Another client quote from the same Southern California consumer "ranking" website (there were only 2):

He entitled it:

"Paolo is the worlds best aquatic designer - insightful, creative, & detailed!"

"The worlds' best - hands down! I have Ex-Presidents as personal friends & now proudly include Paolo among them! I'll fly him anywhere - at any cost, for my next project! We're so glad that we went with our gut instinct and hired Paolo. He operated on a "cost+" basis, and at first we thought that additional travel & hotel expenses, per Diem fees, & material sourcing trips, in addition to the cost+ were crazy. But, we got the best end of the deal & we get to enjoy his artwork everyday!

Though it was against his financial interest, he negotiated the best prices on materials, even importing materials from far flung corners of the world. He saved us hundreds of thousands of dollars on the overall project. I can not express the level of satisfaction, follow through, and design sense he brought to our project.

I can not imagine our pools without him (he has done 3 properties for us)... they'd be an architects boring monochromatic hallucination... instead we got a technicolor dream coat!

We've since brought him in & included him on the design team of a casino, an office building, and a house in the Islands that we are building. We have given him a lot of responsibility and freedom to "do his thing." The hardest part is staying out of his way... when he gets going, he's like the Tasmanian devil on a triple espresso!

So creative, visionary, opinionated, yet likable, and yes expensive - but, I'm proud to include him among my friends. How many clients of my stature, welcome a designer/contractor into their inner family of friends? He is as comfortable on a ranch hunting as in a black tie - at opening night of the Met! A true renaissance man, world traveled, speaks multiple languages, college educated, karate 3rd degree black belt... and a gifted designer/contractor!

I'm also privileged to have one of his early creations... though his visions & creations are hidden away in backyards across the country, THEY WILL BE DISCOVERED AND REVERED LIKE FRANK LLOYD WRIGHT'S or PICASSO'S WORK! His work is beyond description.... and he was always looking out for our best interest!

PROS: Absolutely flawless - a perfect canary yellow diamond!
CONS: Expensive, Qualifies his Clients, a Waiting List - but worth the wait!"

I could have summed that up in three words: "honest, gifted & intense."

Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa

Blowing my own horn!

Paolo Benedetti of Aquatic Technology Pool & Spa - Expert in Vanishing Infinity Negative Disappearing Perimeter Knife Edge Swimming Pools Spa Construction

Every once & a while... we get to blow our own horn!

I recently ran across the following client comment on a Southern California consumer "rating" website:

"For those clients where money is not an object, and who has no problem parting with it, Paolo Benedetti is a true artist. We commissioned a design (for a fee of course), which turned out awesome! He met with us over a period of a few weeks, presenting various options and concepts. He listened to our needs and concerns, and even made a great many observations himself. He really cared about us and our project, ensuring that we do not outgrow its functionality.

We decided to have him build & manage our project, as we had grown very comfortable with him. Though he is located in Northern California, he was here when needed.

We were not in a hurry to be swimming in a few months. And after watching the level of craftsmanship that went into EVERY level of construction, there is no way they could have built our project in any less time. They even mapped out the days for the proper curing of the cements & mortars, to ensure that everything is done by the book.

Our finished project is flawless. A one of a kind creation that seamlessly integrates water into the architecture of our house and landscaping.

We later found out that he was ranked as one of the top 3 builders in the LA area, though he is in San Jose, CA (The Franklin Report). Now we know why he is in such demand. His projects have even appeared in the NY Times, US Today, and on many TV programs.

PROS: Absolute highest construction standards & practices!
CONS: Expensive, but what quality artwork isn't?"

Speaks for itself, now doesn't it?

Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa

Thursday, June 4, 2009

It's cracking because it's only 3.5" thick!

Paolo Benedetti founder of Aquatic Technology Pool & Spa
Vanishing Edge Pool, Infinity Edge Pool, Perimeter Overflow Pool, Slot Overflow pool, Knife Edge Pool, & Disappearing Edge Pool expert

I recently was involved in a construction defect case, where among the many flaws was a substandard pool deck. The flagstone veneer was coming loose all over the place & the grout was cracking.

When I dug back a part of the lawn at the edge of the patio - the truth revealed itself...

The concrete slab under the stone work was only 3.5" thick! To make matters worse, the concrete contractor used 4-5" of crushed dolomite rock for a sub-base. Dolomite rock is very soft crystalline rock that has virtually no load bearing value. And, placing such thin layer of such a fine sub-base allowed the underlying expansive soils to transfer their energy directly into the masonry above.

To add insult to injury, there was a geo-technical investigation (soils report) available to the concrete contractor. But he didn't bother asking if one was available. Now that it has been thrown back into his face, he wish he had asked for it! The soils report made recommendations as to how much of the expansive top soils needed to be removed, what was to be imported, and how the sub-base was to be installed. As it turned out there was supposed to be "24" of compacted 3/4" drain rock" placed under the slab. The report specified "a minimum 6" thick slab with #4 rebar on 12" centers, topped with #10 wire mesh, tied to the surface of the placed reinforcing steel. Reinforcing steel to be supported on the sub-base with 3" concrete blocks or plastic chairs."

In his infinite wisdom, the concrete contractor used #10 wire mesh as his reinforcing steel. And because it is so flimsy and cannot be supported on dobbies (concrete blocks), they left it laying on the sub-base. Lots of good it does there! He stated that as they poured the concrete, he "hooked the wire & lifted it into the center of the slab." I made him a gentleman's wager, that the wire was consistently in the bottom 1/4 of the slab, and would be found mostly on the bottom. He did not realize that once the workers begin to tamp & finish the concrete, the wire settles back down to the bottom. At best, a cross section of the wire in the slab looks like a "wave" throughout the slab.

Then he violated the building codes that specify the clearances from the reinforcing steel to earth and reinforcing steel to the surface of the concrete. The minimum clearance from earth to the BOTTOM SIDE of the reinforcing steel when the concrete is cast against earth is 3 inches! The minimum clearance of the TOP SIDE of the reinforcing steel to the surface of the concrete is 2 inches! So, had he used #4 sized (1/2" diameter) reinforcing steel, the slab would have had to be 6" thick! Since the #4 bars would be laid out in a checkerboard fashion, they cross over each other. This means that the steel is in some places 1" thick (1/2" + 1/2" = 1" thickness of steel at the intersections). 3" of concrete below the steel + 1" steel thickness + 2" of concrete above the steel = a 6" thick slab.

So, any concrete contractor who forms concrete that is to be poured against the earth (that includes the sub-base material) with 2x4 limber is in violation of the building codes (IBC, UBC, or CBC). And any client that contracts for a 4" thick slab is being cheated, as a 2x4 is actually only 3.5" high not 4"!

The stone veneer was mortared directly on top of the concrete slab. As the slab cracked, the cracks migrated through the stonework. The grout cracked & came loose, as did the stones.

Decks of this type of construction need to be built to protect the stonework from failure. The concrete slab should have had thickened edges and turn down footings around the perimeter. There should have been a "crack control" or "cleavage" membrane installed on top of the concrete slab. This membrane prevents cracks in the concrete from migrating through to the stone work - manifesting themselves on the surface.

If ground water or poor site drainage was present, a vapor barrier should have been placed beneath the concrete slab. The crack control membrane could have also been upgraded to a waterproof membrane, adding a layer of protection against efflorescence on the surface of the stone (from water beneath).

The final mistake, which actually caused the ground to start moving in the first place - was that the concrete contractor did not install any surface drainage. Instead, he talked the homeowner into sloping the decks back to the planters & allow the water to run off into the landscaping - saving the homeowner money on a drainage system. Not a good idea, when expansive soils are present. The water migrated back under the concrete slab through the finely crushed dolomite, where it soaked into the soils. Being expansive, the soils swelled, causing movement & cracking of the concrete slab, and cracking & separation of the stone veneer.

The turn-down footing at the edge of a concrete slab, is designed to strengthen the edges of a slab, prevent "slab curl" as it cures, and prevent water from migrating beneath the slab. Surface drainage should always be installed to direct water off of the decks. If the water is being directed to the side of the deck, then a trench drain or french drain needs to be installed to redirect the water away from the sub-base.

Since he failed to inquire or follow the soils report recommendations and relied on his inferior construction practices (e.g. wire mesh, hooking the wire mesh, 3.5" forms), he will bear ALL OF the expenses of jack-hammering & hauling away the current decks, excavating the site 30+ inches, installing a drainage system, importing the proper base rock, properly re-pouring the concrete decks, and reinstalling the stone veneer.

Again, having (and using) the recommendations in a soils report would have saved this contractor a lot of time & money. Had he followed the recommendations and still experienced these same failures, he would not have been liable for their correction.

Do it right, or don't do it!

Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa